1. Field of the Invention
The present invention relates to computer interfaces, in particular, to interfaces for interfacing a compute node to a mesh network and to a method of exchanging data.
2. State of the Art
Massively parallel processing (MPP) systems are becoming increasingly widespread. In an MPP system, a large number of “compute nodes” are placed in communications with one another through a “mesh fabric,” i.e., a collection of interconnections that typically allows any compute node to communicate with any other compute node. MPP systems have been used to solve computational problems once thought to be uncomputable even using supercomputers. MPP systems are also being applied successfully in the area of high-availability computing.
A prime consideration in relation to MPP systems is the scalability of the system: over what range of computational power can the system be configured to operate successfully. A system that successfully exploits the compute power of 64 compute nodes may prove incapable of successfully exploiting the compute power of 6400 compute nodes. In considering scalability, attention is most often focused on the high end. Often equally important, however, is the low end: what base investment is required to join an MPP performance curve that may span orders of magnitude of compute power.
Low- and moderate-cost computer architectures have increasingly embraced the PCI bus as an expansion bus standard. The PCI bus dramatically increases data throughput as compared to previous generation expansion buses. As compared to a high-speed system bus, however, the PCI bus (and expansion buses in general) remains comparatively slow. Furthermore, a coherency protocol of the PCI bus is not widely implemented. There remains a need for a bus interface, or bus bridge, that allows for high-speed, coherent data transfer between an expansion bus such as the PCI bus and a system bus. A further need exists for a bus bridge that allows for high-speed, coherent data transfer between an interconnection mesh and a system bus. The present invention addresses this need.